Electric discharge envelope



mamme DISCHARGE ENVELOPE Filed Jun@ .21, 191m fsa 'Sheetsheet 1 Patented Dec. 20, 1949 ELECTRIC DISCHARGE ENVELOPE Robert Leonard Breadner., Kenton, Henry (3h-ain-` ger Jenkins, Pinner, and Charles Henry Simms,l Twickenham, England, assig-nors to` General Electric Company, a corporation of New York Application June 21, 1946, Serial No. 678,220 In Great BritainY March 21, 19.45

Section 1, Public Law 690 August 8, 194.6 Patent expires March 21 1965 The present invention relates to electric discharge lamps generally, and more particularly to lamps of the kind in which the discharge passage between one or more pairs of electrodes is a channel formed between two vitreous components sealed together, one or both of the components having one or more upstanding ridges which separate adjacent parts of the discharge passage from one another.

One example of a discharge lamp of this kind has a discharge passage formed between two molded glass components each having a spiral depression or groove of approximately semi-circular cross-section extending from near the periphery to the center. These two components are sealed together around their periphery with the upstanding ridges which separate the depressions in register with one another thus forming a spiral channel of approximately circular cross-section. Electrodes are arranged at the two ends of the channel.

It has been found sufcient, in lamps of the type described using molded components where close contact can be established between the upstanding ridges by grinding for example, to seal the two components together only around the outer periphery to enable the spiral channel to be evacuated. The opposing faces of the upstanding ridges on the two components are arranged to abut or to lie close enough together to prevent leakage of the discharge between adjacent parts of the channel.

In constructing lamps of the design just described, diiiiculty has been met with owing to the fact that the two peripheral walls of the tWo components which have to be sealed together are not of uniform width owing to the upstanding spiral ridges merging in one region into these walls. This lack of uniformity renders it diflicult to avoid cracks particularly when quantity production methods are employed. The same dillculty is encountered with many other shapes of discharge passage.

It is the object of the present invention to provide a construction of discharge lamp of the kind set forth in which the difficulty referred to is overcome.

According to the present invention there is provided an electric discharge lamp of the kind specified in which the crests of the upstanding ridges on one component are arranged to abut or to lie close enough to the other component, without sealing, to prevent substantial leakage te! the discharge, and in which said upstanding ridge merges into an outer wall forming a bound- 8 Claims. (Cl. 17d-122) 24 ary of the discharge passage which wall is of non-uniform width, wherein there is provided on at least one of the components, outside of or beyond said outer wall, a flange of substantially uniform width which is sealed to the other component to form a vacuum-tight closure to the discharge passage. The wall structure may be considered as separate from the outer flange or flanges, or the flanges may be considered as comprising part ofthe total wall structure.

When both components have upstanding ridges both are provided with flanges which are sealed together to form the vacuum-tight closure.

If, however, only one of the components isv ridged and the other is for example in the form of a flat disc, a cylinder, a conical frustum or the like which is plain and unridged, no flange is required on this second component. The flange on the ridged component is then sealed to the surface or edge of the second component.

The invention will be described by way of example with reference to the accompanying drawings in which:

Figs. 1 and 3 are views in underside plan and plan respectively of two components of one lamp according to the invention. f Fig. 2 is a view in sectional elevation and to an enlarged scale of the lamp components of Figs. 1 and 3 with the components placed together.

Figs. 4 and 5 are views in sectional elevation of two other forms of lamp according to the invention.

Fig. 4a is a modification of the structure shown in Fig. 4.

Referring to Figs. 1-3, inclusive, in this example both the upper component la and the lower component Il are provided with upstanding ridges l2 and I3 respectively These ridges bound channels I4 and I5 respectively of substantially semi-circular cross-section. The two components are conveniently formed in suitable moulds by pressing. The crests of the ridges I2 and I3 which are shown abutting in Fig. 2 are made flat and co-planar, either by adequate care in manufacture or by subsequent grinding for example, whereby when the components are placed as shown in Fig. 2 the boundaries between adjacent parts of the discharge passage constituted bythe abutting ridges are effective in substantially preventing a leakage of discharge from one part of the passage to the adjacent part through the junction between the ridges.

It will be seen in Figs. 1 and 3 that the outer fr parts I6V and lll of the. upstanding ridges which form the outer walls or boundaries of the discharge passage are not of uniform width, since the spiral ridges merge into these outer parts at it and i9, respectively. If these outer ridges I6 and H were sealed together by fusion therefore, considerable care would be needed in the sealing operation in order to avoid the introduction of undesirable stresses and even fractures in the glass.

There are therefore provided outside of the outer walls I6 and il' flanges 2li and 2| respectively Which have abutting surfaces of uniform, and preferably the same, Width. These flanges are sealed together by fusion in any convenient Way in order to provide a vacuum-tight or hermetic closure for the discharge passage.

Tubulations 22 and 23 are provided upon the component ld and electrodes (not shown, 'but which may comprise conventional coiled tungsten Wire filaments coated with activating materials such as barium and strontium oxides, and bridging the respective pairs of pins 2d and 25) are mounted on pins 24 and 25 within these tubulations. The inside of the walls of the spiral discharge passage may be coated with a uorescent powder, and the Vpassage may then be evacuated, lled with a suitable gas or vapor and sealed oi at an exhaust tube 2B. Tribulations 22 and 23 may be provided with caps or bases 22a and 23a, respectively, which seal the tubulations and support the contact terminals or pins 24 and 25.

Referring to Fig. 4, the upper component I is of similar design to that of Figs. 1 to 3 and like parts are given the same references. lower component 27 is in this example a fiat disc of glass. In this case it is clearly not necessary to provide a ange upon the component 21 for sealing purposes in order to avoid the introduction of undesirable stresses. The flange 2G is therefore provided only upon the ridged component lli and this flange is sealed to the outer part of the disc 2l.V The flange 2i! could lf desired extend over the edge 28 of the disc and be sealed to this edge. A further modification of the structure shown in Fig. 4 is illustrated in Fig. 4a, wherein the outermost ridge or flange 20 extends over the edge 28 and is sealed to the disc at or on this edge. Only one of the tubulations 22 and one pair of electrode supporting pins 24 is shown in Fig. 4 but the second may be arranged as shown in Figs. 1 and 2.

In Fig. the lamp is of a generally cylindrical shape and comprises a ridged inner component 29 and a plain (unridged) cylindrical outer component Sli. The two components are arranged to be in close contact with one another along the upstanding helical ridge 3l. In this case the discharge passage 32 is of helical shape and has a cross-section of approximately semicircular shape. A tube 33 connecting with the lower end of the passage 32 may contain electrodes and a similar tube (not shown) also containing electrodes is arranged in connection with the upper end of the passage 32.

The two outer or boundary Walls 34vand 35 are evidently not of uniform Width and there are provided in accordance with the invention, fianges 35 and 3f of uniform Width which are outside of or beyond the outer walls 3d and 35 respectively and which are sealed to the cylindrical outer component 30.

What we claim as new and desire to secure by Letters Patent of the United States is:

` l. -In a hermetic enclosure-for an electrlc.dis-.

The

charge device, the combination comprising a pair of components at least one of which is provided with a raised ridge to abut without sealing to a portion of the other component'thereby to prevent substantial leakage of an electric discharge, said ridge merging into an outer wall forming a boundary of a discharge path defined by said ridge, the ridged component being provided at the outer side of said wall With an outer flange of uniform Width having its edge concentric with and spaced from said Wall and deningwith said wall a plural annular anged construction, the said ridged component being fused to the other component along said outer flange only.

2. In a hermetic enclosure for an electric discharge device, the combination comprising al pair of components at least one of which is provided with a raised spiral ridge to abut without sealing to a portion of the other component thereby to prevent substantial leakage of an electric discharge, said ridge merging into an outer wall forming a boundary of a spiral discharge path defined by said ridge, the ridged component being provided at the outer side of said wall with an outer iiange of uniform width having its edge concentric with and spaced from said wall and defining with said wall a plural annular anged construction, the said ridged component being fused to the other component along said outer flange only.

3. In a hermetic enclosure for an electric discharge device, the combination comprising a pair of circular components each of which is provided with a raised ridge to abut without sealing to a portion of the other component thereby to prevent substantial leakage of an electric discharge, said ridge merging into an outer Wall forming a boundary of a discharge path defined by said ridge, the outer side of said Wall being provided with an outer flange of uniform width having its edge concentric with and spaced from said wall and defining with said Wall a plural annular flanged construction, the said components being fused together along their outer flanges only.

4. In a hermetic enclosure for an electric discharge device, the combination comprising a pair of circular components each of which is provided with a raised spiral ridge to abut without sealing to a portion. of the other component thereby to prevent substantial leakage of an electric discharge, said ridge merging into a circular outer Wall forming a boundary of a spiral discharge path dened by said ridge, the outer side of said wall being provided with an outer flange of uniform Width having its edge concentric with and spaced from said wall and dening with said Wall a plural annular anged construction, the said components being fused together along their outer flanges only.

5. In a hermetic enclosure foran electric dis-- charge device, the combination comprising a pair of components one of which comprises a disc and the other of which is provided with a raised ridge.

to abut without sealing to a portion of the disc component thereby to prevent substantial leakage of an electric discharge, said ridge merging into an outer wall forming a boundary of a discharge path defined by said ridge, the ridged component being provided at the outer side of said Wall with an outer flange of uniform width having its edge` concentric with and spaced from said walland defining with said wall a pluralannular 'flanged construction, the said ridged componentbeingl fused to the disc component along said outer flange only.

6. In a hermetic enclosure for an electric discharge device, the combination comprising a pair of circular components one of which comprises a disc and the other of which is provided with a raised spiral ridge to abut without sealing to a portion of the disc component thereby to prevent substantial leakage of an electric discharge, said ridge merging into a circular outer Wall forming a boundary of a spiral discharge path defined by said ridge, the ridged component being provided at the outer side of said wall with an outer flange of uniform Width having its edge concentric With and spaced from said wall and defining with said wall a plural annular anged construction, the said ridged component being fused to the disc component along said outer flange only.

7. In a hermetic enclosure for an electric discharge lamp, the combination comprising outer and inner cylindrical-shaped components, one of said components being formed to have a raised ridge having a flat crest to abut without sealing to the other component and merging into outer Walls at each end of the component, each of said walls being provided at its outer side With an outer flange of uniform Width having its edge concentric with and spaced from said wall and dening with said Wall a plural annular flanged construction, the ridged component being fused to the other component along said outer flange only.

8. In a hermetic enclosure for an electric discharge lamp, the combination comprising outer and inner cylindrical-shaped components, one of said components being formed to have a raised helical ridge having a flat crest to abut Without sealing to the other component and merging into outer Walls at each end of the component, each oi said Walls being provided at its outer side with an outer flange of uniform Width having its edge concentric with and spaced from said Wall and dening With said Wall a plural annular flanged construction, the ridged component being fused to the other component along said outer flange only.

ROBERT LEONARD BREADNER. HENRY GRAINGER JENKINS. CHARLES HENRY SIMMS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,867,154 Hotchner (a) July 12, 1932 1,926,552 Morgan 1 Sept. 12, 1933 1,935,423 Wayringer Nov. 14, 1933 1,934,215 Hotchner (b) Dec. 11,. 1934 2,205,672 Sawyer June 25, 1940 2,255,431 Marden (a) Sept. 9 1941 2,316,348 Mahlck Apr. 13 1943 

